function add(x, y) {
  console.log(arguments.length);
  const res = Array.from(arguments);
  console.log(JSON.stringify(arguments));
  return x + y;
}

console.log(add(1));
console.log(add(1, 2));
console.log(add(1, 2, 3));

let myAdd = function(x, y) {
  return x + y;
};
